Chemical Waste Management and Disposal

  

Chemical Waste Management and Disposal

Waste Management

  • Nonhazardous waste
  • General guidelines- Storage - Packaging

    Special categories
    • Metal waste
    • Radioactive and mixed waste
    • Biological waste
    • Unknown and orphan waste

  • Treat on-site

Waste management: nonhazardous waste

  • Used oil (uncontaminated) is not considered hazardous

  waste. Label Containers "USED OIL", not "hazardous waste."

  • Uncontaminated PPE (gloves, wipes)
  • Triply rinsed glassware (bottles, droppers, pipettes)
  • Salts (KCl, NaCl, Na CO )

  2

  3

  • Sugars - Amino acids
  • Inert materials (uncontaminated resins and gels)

Waste management: General guidelines

  • Secure and lock waste storage area
  • Post signs to warn others
  • Keep area well ventilated
  • Provide fire extinguishers and alarms, spill kits
  • Provide suitable PPE
  • Provide eye wash, safety showers
  • Do not work alone

Waste management: General guidelines

  • Insure against leakage; dyke area

  if possible

  • Label all chemicals, containers,

  vials

  • Separate incompatible chemicals
  • Keep gas cylinders separate
  • Keep radioactive material separate
  • Know how long waste can be

  stored

  • Provide for timely pick-up

Waste - Storage guidance

  • Container should not react with the waste

  being stored (e.g. no hydrofluoric acid in glass).

  • Similar wastes may be mixed if they are

  compatible wastes from

  • Whenever possible,

  incompatible hazard classes should not be mixed (e.g. organic solvents with oxidizers).

  • Containers must be kept closed except

  during actual transfers. Do not leave a funnel in a hazardous waste container.

  • Chemical containers that have been triple-

  rinsed and air-dried in a ventilated area can be placed in the trash or recycled.

  Waste – General guidance Certain metals cause disposal problems when mixed with flammable liquids or other organic liquids Pressure can build up in a waste vessel Corrosion can occur in storage vessel Secondary containment is necessary Glass waste containers can break

  

Dangerous waste management

  

Video – Fire at Apex Waste Facility

  

Best practice – Orphan control

Before moving to new job meet with new lab occupant

  • This can be a new employee or new student
  • Label all chemicals and samples carefully
  • Make notations in common lab book

Dispose of all unneeded or excess chemicals

  • Put into chemical exchange program
  • Dispose of as hazardous waste

  

Do not leave any chemicals behind except by agreement

Waste management

  • Recycle, reuse, redistill, if possible
  • Dispose by incineration, if possible
  • Incineration is NOT the same as open burning

Emissions from incineration vs. open burning Open Municipal Burn Waste Incinerator (µg/kg) (µg/kg) PCDDs 38 0.002 PCDFs 6 0.002 Chlorobenzenes 424150

  1.2 PAHs 66035

  17 VOCs 4277500

  1.2 Source: EPA/600/SR-97/134 March 1998

  Lab packs consists of small containers of compatible waste, packed in absorbent materials. Lab packs segregated at hazardous waste facility Laboratory wastes are packaged in small containers

Waste management: Waste disposal service

  • Is disposal service

  licensed?

  • How will waste be

  transported?

  • How will waste be

  packaged?

  • Where will material be

  disposed?

  • How will it be disposed?
  • Maintain written records

Battery recycling and disposal Hazardous waste

  • Lead acid (Pb) - recycle (90% car batteries)
  • Sealed lead (Pb) - recycle
  • Mercury-oxide (HgO) button, silver-oxide

  (AgO) button - recycled by jewelers

  • Nickel Cadmium (NiCd) recycle

Nonhazardous waste

  • Nickel Metal Hydride (Ni-MH) recycle
  • Carbon – zinc
  • AlkalineZinc-air button

Mercury metal disposal

  • Collect pure liquid mercury in a sealable

  container. Label as "MERCURY FOR RECLAMATION"

  • Place broken thermometers and mercury

  debris in a sturdy sealable plastic bag, plastic or glass jar. Label the container "Hazardous Waste - MERCURY SPILL DEBRIS" .

  • Never use a regular vacuum to clean up a

  mercury spill - contaminates vacuum, heat evaporates the mercury

  • Never use a broom to clean up mercury –

  spreads smaller beads - contaminates the broom.

  Mixed Waste (chemical radioactive) These wastes must be minimized - heavily regulated Universities, hospitals Low level radioactive with chemical Scintillation cocktails Gel electrophoresis waste Nuclear energy research Low and high level radioactive with chemical Lead contaminated with radioactivity

Mixed Waste (chemical-biological)

  • Medical wastes
    • Blood and tissue
    • Sharps – needles, scalpels
    • Contaminated glassware, ppe

  • Autoclave or sterilize
    • Bleach incompatible with autoclave
    • Do not autoclave flammable liquids

  • Incinerate

Mixed Waste (radioactive-biological) Medical wastes

  • Often disinfect high biohazard

  to minimize handling risk

  • Let short-lived isotopes decay

  and then use sanitary sewer

  • Refrigerated storage for

  putrescible waste (carcasses- tissue)

  • Autoclave or disinfect labware

  and treat as low level radioactive

  • On-site incineration of low

  level rad waste if permitted (sharps as well)

Unknown “orphan” waste

  

Avoid if at all possible -- requires analysis before disposal!

Pre-screen Crystals present ? (potential peroxide formation) Radioactive (Geiger counter) Bio waste? (interview history) Screen Prepare for the worst – wear gloves-goggles-hood Air reactivity Water reactivity Flammability Corrosivity

Unknown waste characterization* Physical description - Water reactivity - Water solubility pH and neutralization information Presence of:

   OxidizerSulfides or cyanidesHalogensRadioactive materialsBiohazardsToxics

  • *Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy

    Press, 1995 Section 7.B.1

Waste management: Down the drain? If legally allowed:

  • Deactivate & neutralize some

  liquid wastes yourself

  • e.g., acids & bases
  • Don’t corrode drain pipes
    • Dilute with lots of water while

  pouring down the drain

  • Be sure that you do not form

  more hazardous substances

  • Check reference books,

  scientific literature, internet

Treating on site – volume reduction Evaporation – if not excessive

  • Roto evaporation for recovery
  • Do not evaporate corrosives or

  radioactives

  • Only in laboratory hood
  • Beware toxics and flammables

Adsorption

  • Activated carbon
  • Ion exchange resin
  • Activated alumina

  Precipitation - Extraction Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, 1986. ISBN 0-85312-634-8

Treating on site – chemical conversion Requires chemical expertise - may not be allowed by regulations - specific to each chemical Dilution to reduce hazard

  • H O , HClO , HNO

  2

  2

  4

  3

  • Never add water to concentrated acid
  • Neutralization acid base -gentle

Hydrolysis (acid and base)

  • Active halogen compounds with NaOH
  • Carboxamides with HCl

  Oxidation-reduction Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, 1986. ISBN 0-85312-634-8

Chemical Waste Example: Tollens Reagent Ag(NH ) NO (aq)

  

3

  2

  3

  • The reagent should be freshly prepared and stored

  refrigerated in a dark glass container. It has a shelf- life of ~24 hours when stored in this way.

  • After the test has been performed, the resulting

  mixture should be acidified with dilute acid before disposal. These precautions are to prevent the formation of the highly explosive silver nitride.

Waste management: Treatment in Lab

  • References:
    • “Procedures for the Laboratory-Scale Treatment of

  Surplus and Waste Chemicals, Section 7.D in Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy Press, 1995, available online:

  • “Destruction of Hazardous Chemicals in the Laboratory,

    nd

  2 Edition”, George Lunn and Eric B. Sansone, Wiley Interscience, 1994, ISBN 978-0471573999.

  • “Hazardous Laboratory Chemicals Disposal Guide, Third

  Edition”, Margaret-Ann Armour, CRC Press, ISBN 978- 1566705677

  • “Handbook of Laboratory Waste Disposal”, Martin Pitt

  and Eva Pitt, 1986. ISBN 0-85312-634-8

  

On-site Recycling and Waste Treatment

  Waste Management: Recycling Recycling by redistribution Recycling of metals Gold-mercury–lead- silver Recycling of solvents Clean for reuse-rotovap Distill for purity Recycling of oil Recycling of E-waste

Chemical recycling

  

Reuse by others in the organization or community

An active chemical exchange program Beware of accepting unusable chemicals Reuse in experiments in the laboratory Exchange for credit with suppliers by agreement

What should not be recycled

  • Gas cylinders past their pressure testing date
  • Used disposable pipettes and syringes
  • Chemicals and assay kits past their expiration
  • Obviously degraded chemicals
  • Used tubing, gloves and wipes
  • Others?

What should be recycled or redistributed?

  • Excess unopened chemicals
  • Excess laboratory glassware (unused or clean)
  • Consumables with no expiration
  • Solvent that can be purified>Lower purity suitable for secondary use?
  • Precious or toxic metals
  • Hg, Ag, Pt, Pd, Au, Os, Ir, Rh, RuOthers?

Chemical Recycling - Precious Metal For reuse in lab or for exchange

  • Requires chemical knowledge for lab reuse
  • Recover from solution - evaporate then
  • Ignite (Au, Pd, Pt)

  for metal powder or

  • Reduce with NaBH

  4 by electroless plating (Pt, Au, Pd, Ag, Rh).

  • ElectroplateMetal recovery Ion exchange-then ash

  Source : Handbook of Laboratory Waste Disposal, Pitt &Pitt, John Wiley, 1986

Chemical Recycling - Silver Recovery from chemical oxygen demand (COD) test

  • Acidification and ppt as AgCl

Recovery from photographic fixing solution

  • Precipitate as sulfide
  • Precipitate with TMT (trimercapto-s-

  triazine)

  • Electrolysis (terminal and in-line)
  • Metal replacement (iron containing

  cartridges)

  • Ion exchange

  Many companies will buy the recovered

Chemical Recycling - Mercury

  • Mercury can be recovered for

  subsequent lab use or for recycle by vendor

  • Remove particulates and moisture

  by allowing slow drip through a hole in a conical filter paper

  • Never distill Hg on-site

Solvents can be recovered by distillation

  • Boiling point must be widely

  different

  • Azeotropes may prevent

  separation

  • Sometimes hazards are created
  • Some solvents do not need

  complete separation

  • Hardware for separation

Solvent recycling – general guidance Solvent recycling requires care and organization

  • Keep solvents segregated

  prior to separation (single product solvent)

  • No unnecessary dirt due to

  careless handling

  • Requires good labeling
  • A small amount of the wrong

  chemical can ruin a desired separation

  • Care must be taken not to

  concentrate peroxides

Solvent recycling – general guidance Solvent recycling requires care and organization

  • Try other purification methods before

  distillation

  • Convert to precipitate
  • Convert to water soluble
  • Use an adsorbent>Need BP difference of > 10°C
  • Can form azeotrope*>water / ethanol (100°C/ 78.3°C)
  • cyclohexane / isobutanol (81°C / 108°C)
  • Mixture of 4 solvents not practical
  • Distillation can be incorporated into

  curriculum * Consult CRC Handbook of Chemistry and Physics for list of azeotropes

Solvent recycling – low efficiency Rotovap can be used to pretreat

  • Toxic material may be kept

  from the distillation

  • May be sufficient if purity is

  not crucial

  • Separation of solvent from

  solids

Solvent recycling – basics

  Reflux ratio TP 120

  25 Reflux

  80

  24 Distillate

  40

  21

  20

  16

  10

  10

  4

  leads to increased separation efficiency TP = theoretical plates

Solvent recycling – medium efficiency

  • Even high efficiency stills are not

Example: 200mm long perfect

  column for separating

  • Continuous better than batch for

  benzene and toluene large volumes

  • Control reflux

Packing TP

  • Monitor head temperature

  Empty

  0.5

  • Reduce heat loss to get more

  efficiency Coarse packing

  1

  • Do not let still operate to dryness

  Fine packing

  5

  • Use boiling chips but do not add

  when solvent is hot

  TP = theoretical plates

  

Diagram of packed and spinning band

distillation columns

Diagrams from B/R Instruments: http://www.brinstrument.com/

Boiling point of common solvents (C) Halogen Containing

  CH Cl Dichloromethane

  40 2 2 CH Cl Chloroform

  61.6 3 CCl Carbontetrachloride

  76.5 4 C H Cl Trichloroethane

  87 2 3 3 C Cl Perchloroethylene or Tetrachloroethylene 121 2 4 C HCl

  Trichloroethylene

  87 2 3 C H Cl Trichlorobenzene (TCB)

  208.5 6 3 3

Boiling point of common solvents (C) Oxygen Containing

  C H O Acetone

  56.1 3 6 C H O MEK (Methyl ethyl ketone)

  79.6 4 8 C H O Acetic acid

  118.1 2 4 2 C H O Ethyl acetate

  77 4 8 2 C H O Ethylene glycol 197 2 6 2 C H O

  Propylene glycol 187 3 8 2 C H O Ethyl ether

  34.5 4 10 C H O THF (tetrahydrofuran)

  66 4 8 C H O MIBK (Methyl isobutyl ketone) 116.8 6 12

Boiling point of common solvents (C)

  

Oxygen Containing (cont)

  CH O Methanol

  64.5 4 C H O Ethanol

  78.3 2 6 C H O n-Propanol

  97 3 8 C H O Isopropanol

  82.5 3 8 C H O n-Butanol 117.2 4 10 C H O sec-Butanol

  99.5 4 10

Boiling point of common solvents (°C) Hydrocarbons

   C H n-Pentane

  36.1 5 12 C H n-Hexane

  68.7 6 14 C H Cyclohexane

  80.7 6 12 C H n-Heptane

  98.4 7 16 C H n-Octane/iso-octane 125.7 / 117.7 8 18 C H Toluene

  110 7 8 C H Ethylbenzene 136.2 8 10 C H p/m/o-Xylene 138.3 / 139.1 / 144.4 8 10

Boiling point of common solvents (C) Nitrogen Containing

  C H N Pyridine 115 5 5 C H N

  Aniline 184 6 7 C H NO n,n-Dimethylformamide 149-156 3 7 C H NO n-Methylpyrolidone

  202 5 9 C H N Piperdine

  106 5 11 C H N Acetonitrile

  81.6 2 3

Solvents that should not be recycled by distillation

  

Accidents have been reported for these distillations

Individual Substances

  • Di-isopropyl ether (isopropyl alcohol)
  • NitromethaneTetrahydrofuranVinylidene chloride (1,1 dichloroethylene)

Mixtures

  • Chloroform + acetone
  • Any ether + any ketone
  • Isopropyl alcohol + any ketone
  • Any nitro compound + any amine

Practical examples of recycling

  • Hexane contaminated with small amount of

  inert solvent used in prep lab

  • Chemistry students given a finite quantity of

  solvent, then had to recycle for subsequent experimentsAcetone 50% in water for washing. Azeotrope is 88.5% which is then diluted back with water for reuse

  • Use rotovap recovery rather than

  evaporation. Student will redistill; 60% recovery.

  • Third wash was captured and used as first

  wash on next experiment Source : Handbook of Laboratory Waste Disposal, 1986.

  Marion Pitt and Eva Pitt, John Wiley and Sons, ISBN 85312-634-8

Solvent recycling Automated systems help with large needs

  HPLC Solvent Recycling GPC Solvent Recycling Environmental Laboratory Solvent Recycling Freon Solvent Recycling Histology Laboratory Solvent Recycling General Lab Solvent Recycling Services Can also be Purchased

  Pictures from B/R Instruments: http://www.brinstrument.com/

  

Any Questions?